Over a third of individuals with bipolar spectrum disorders (BP) are treated exclusively in primary care settings, and yet, primary care providers (PCPs) are ill-equipped to manage this complex and disabling illness. Medications, which can be prescribed by PCPs, hasten recovery from illness and improve long-term course of illness for those with BP, but relapse and residual symptoms are common when individuals are treated with pharmacotherapy alone. Best practices treatment for BP includes adjunctive, BP-specific psychotherapy as a key element of effective care. And yet, evidence-based BP-specific psychotherapies that engage and modify targets specific to BP are typically unavailable in primary care settings. Online interventions have the potential to overcome barriers to accessing evidence- based psychosocial treatments for BP in primary care. In other settings and with other populations, effectiveness of online interventions improved when human support/coaching (clinical helpers; CH) via text, email, and telephone was added to the intervention. Interpersonal and Social Rhythm Therapy (IPSRT) is a BP-specific psychotherapy that uses a problem-solving approach to help individuals regularize their social rhythms in order to entrain underlying disturbances in circadian and sleep/wake regulation, factors that are increasingly recognized as playing important roles in the pathogenesis of BP. Its primary behavioral target is regularity of daily routines such as sleep/wake cycle and mealtimes. This construct is measured by the validated Social Rhythm Metric (SRM). The current application seeks to develop and conduct initial testing of an online version of IPSRT (i-IPSRT) for use in primary care. We will (1) evaluate the feasibility and acceptability of supported and unsupported online psychotherapy interventions for BP in primary care (i- IPSRT and i-IPSRT plus CH) compared to Control Condition (CC), (2) examine whether i- IPSRT and i-IPSRT + CH engages its primary behavioral target as measured by the SRM, and (3) explore the impact of i-IPSRT, i-IPSRT + CH, and CC on symptoms and functioning over 12 weeks. Information from this study will inform a larger trial to test the effectiveness of these approaches in primary care. The public health impact of developing an effective, technology- enabled approach to delivering evidenced-based psychotherapy that targets specific, modifiable, behaviors for BP in primary care settings is substantial, offering the potential to reduce illness burden and improve outcomes for individuals with this disabling disorder.